1. Field of the Invention
The invention pertains to the field of exercise machines and more particularly to exercise apparatus for leg presses, leg curls and leg extensions.
2. State of the Art
Exercise of the lower body has always been problematic, for strength conditioning in particular. The lower body has no hands. Therefore, unlike upper-body exercise, exercise of the legs does not have the benefit of prehensile digits and an opposed thumb for grasping a bar or handle to draw or drive a resistance or weight at will. Running, stepping, walking in all their forms limit the exercise participants to their own body weight.
Various exercise equipment may be employed while running or performing other exercises with legs. A user may add weight by means of barbells, or other lifting mechanisms. However, such devices often incidentally load the spine, shoulders, neck and torso as well as the legs. Such incidental loading can result in disproportionate conditioning and excessive strain or overwork for the upper body structure and muscles. Thus, when desiring to exercise a specific lower body muscle group, a user should ideally work out on an exercise machine which will isolate the motion and the loading of that specific muscle group.
Various exercise machines have a bench system for permitting a user to lie down on the back or stomach while working loaded levers or the like with the legs. Other machines permit a sitting or standing user to operate a padded harness attached to a weight or other resistance system. Some machines combine several movable elements with resistances in several configurations for performance of multiple exercises. Various stations may be arranged around a frame of an exercise machine for consolidating some functions of the machine offered by a variety of stations. Likewise, such machines are often most useful or economical if each station is adaptable for use in a number of exercises.
Several limitations arise however, in such state-of-the-art lower body exercise machines. Several different mechanisms are required to permit all the desired motions and loadings, loading being the force or resistance exerted by the machine on a user during the motions of an exercise. A user, particularly at home, often has insufficient financial resources to purchase the number or complexity of machines needed to achieve the desired range of exercises. Moreover, a home user often has limited space. Therefore, it is desirable to consolidate several types of exercise apparatus into a single machine, and such consolidation of features has often been attempted to reduce cost and size to manageable levels.
Numerous varieties of multiple-exercise apparatus for exercising the upper and the lower body have been marketed. In many, the resistance and distance of motion required by one muscle group are invariably different than those required by another muscle group. Therefore, any consolidation of the resistance mechanisms must result in a machine having an adjustment system for varying the mechanical advantage of the user against the resistance. Since the machines typically allow a series of exercises to be performed by engagement of various moveable members, they typically require reconfiguration. Adjustment of positions, engagement and disengagement of levers and resistances or weights and the like allow various members to serve multiple functions.
However, many such machines require substantial time for rearrangement to permit different exercises. A user must interrupt a series of repetitions of one exercise to configure or adjust the exercise machine for another series. Moreover, during an exercise session, a user will preferably "rotate" several times through a routine of several series of repetitions or "reps" of exercises. That is, a routine is established for exercising several muscle groups, one at a time, each with a series of repetitions. Then the entire routine is repeated. Thus, each muscle group is exercised for a time, then rested for a longer time while several other groups are exercised in turn. When several exercises of the series require some reconfiguration of an exercise machine, substantial time is wasted. A user would usually prefer to move smoothly from one exercise to the next in a routine without moving or dismounting from the exercise machine except possibly to change user position for properly executing a new exercise. Dismounting from the machine to reconfigure it can be extremely inconvenient.
The legs do not get a full range of motion by walking, running or many other exercises, but need specific motions and loads to properly develop all the muscles groups therein. Given the shape of the legs, and their ability to bend significantly in only one direction, most apparatus useful for leg lifts or extensions must be adjusted considerably to be converted to leg curls and further reconfigured for presses, if capable of such reconfiguration at all. Moreover, in each such exercise, the exercise apparatus must contact the leg at a very different location, move in a unique motion and, relative to the user, be in a unique position. In fact, since the feet are not prehensile, considerable attention must be devoted to machine designs for engaging the legs in exercises.
In summary, the combination of a multi-station exercise machine is seldom able to meet the many constraints of size, cost, simplicity, and universality. Nowhere are these constraints more evident than with machines for leg exercises. The various motions of the legs are substantially different once the leg is engaged to move against the resistance as well. Thus, what is needed is a machine which can accommodate leg extensions or lifts, leg curls and leg presses from a single station with minimal adjustment, preferably by a user from a single position with a minimal number of machine members. A system which does not require the hands nor require the user to leave a position at an exercising station is preferable. Compactness of all required apparatus in a single unit is highly desirable. Use in several different exercises of various moveable members, without disconnecting, reattaching, reconfiguring or repositioning those members is likewise highly desirable.